Surgical bone anchoring device

ABSTRACT

A bone anchoring device including a thread ( 1 ) whose middle part is in the form of a closed loop ( 2 ), and a deformable sleeve ( 5 ) which can slide on the thread ( 1 ) within the limits of the closed loop ( 2 ), wherein the deformable sleeve ( 5 ) can be deform into a ball by traction exerted on at least one strand ( 3, 4 ) of the thread ( 1 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a surgical device for bone anchoring,and more particularly to a surgical device permitting simple andeffective anchoring of suture thread or surgical thread on a bonesupport, in particular in orthopedic surgery, trauma surgery,gynecological surgery and cancer surgery.

2. Description of the Related Art

Tearing of tendons or of ligaments is something which can happen to manyindividuals of all ages, whether active or inactive, following traumasor excessive strains. The reparative surgical techniques currently usedconsist in attaching the tendon, by means of a suture thread, to ascrew, a peg or a piton fixed in the adjoining bone.

To do this, the conventional technique consists in boring, in the bone,either a tapped hole, so that a screw or piton can be screwed into it,or an untapped hole receiving a peg which can be locked in the bone. Thescrew, the piton or the peg serves as an anchoring means on which onethen attaches a suture thread which is used to re-attach the tendonwhich has been torn from its bone support. In other techniques, after ahole has been bored which is able to receive an anchoring piton, thesuture thread is passed through the eye of the anchoring piton, then thelatter is introduced into the hole by means of a special instrument, andfinally the tendon to be fixed is sutured. An example of an anchoringscrew for fixing tissues by means of a suture thread is described in thepatent U.S. Pat. No. 5,443,482.

Depending on the circumstances, the operations can be performed by opensurgery or by closed surgery using celioscopy or arthroscopy procedures.Surgical techniques using devices of this type are described, forexample, by F. A. Barber et al., J. of Arthroscopy and Related Surgery,vol. 11, No. 1, pages 21 to 28 (1995).

The patent U.S. Pat. No. 5,403,348 describes a bone-anchoring devicecomprising a rigid cylindrical component with a surgical thread passingalong its axis, which is introduced into a hole bored in the bone, asfar as the spongy substance. By acting on the thread, the orientation ofthe cylindrical component is modified in such a way as to block it underthe solid superficial layer of the cortical bone, deforming the spongysubstance.

The patent EP-A-611,551 describes an anchoring device for a suturethread, including a rivet intended to be fixed in the bone support,formed by two elements: a spike, and a rigid sleeve in which it canslide. Another anchoring device is described in the patent U.S. Pat. No.5,584,695, comprising a rivet with shape memory, capable of beingintroduced in the cold state into the bone support and of expanding inthe hot state so as to cause blocking.

These known devices have various disadvantages. They are highly invasiveand are non-absorbable, and their positioning involves techniques whichare often awkward to perform. Moreover, some of the known devicesinclude items containing allergenic materials, for example certainshape-memory materials, and according to some authors these materialsare sometimes carcinogenic. In addition, a large number of screws, pegsor pitons, of accessories for boring into the bone and of accessoriesfor positioning the anchoring means must be available in various sizesso as to be able to respond to all situations.

SUMMARY OF THE INVENTION

The subject of the present invention is a bone-anchoring device whichnecessitates only the prior boring of a single hole with any wall shape,without requiring tapping, and permitting fixation of organs such astendons and ligaments, or suspension of the cervix of the uterus, usinga surgical thread or a suture thread without the need to use a means ofthe screw or piton type.

The invention also describes an ancillary instrument specially adaptedfor placing the aforementioned anchoring device in position.

The anchoring device according to the present invention can be used incombination with a hole bored in the bone support, and it comprises adeformable tubular sleeve, associated with means capable of deforming itbetween a first stretched position of small diameter and a second foldedposition of greater diameter.

The length of the tubular sleeve in the stretched position must besubstantially greater than the diameter to ensure maximum efficacy ofthe device. More precisely, the length of the sleeve must be equal to atleast 5 times the diameter, and preferably at least ten times theexternal diameter of the sleeve.

According to the invention, the means capable of deforming the sleeveare made up of a thread passing through the deformable tubular sleevealong its axis and forming a closed loop, the tubular sleeve beinglocated on the thread, in the loop-shaped part. The internal diameter ofthe sleeve must be sufficient to contain the thread without causing toogreat a frictional force. By way of example, a tubular sleeve can beused having a length of between about 15 and 30 mm, an external diameterof between 1 and 2 mm, and an internal diameter of between 0.6 and 1.2mm.

Thus, in its preferred embodiment, the boneanchoring device of theinvention comprises a thread having a middle part intended to beintroduced into the hole bored beforehand, having a closed loop shape,bearing on the loop-shaped part a deformable tubular envelope or sleevewhich is able to slide on the thread within the limits of the loop. Theclosure of the loop can be obtained by simple crossing of the twostrands of the thread, on either side of the deformable sleeve. Thetubular sleeve can be deformed into a ball by simple traction exerted onat least one strand of the thread.

According to the present invention, the thread used is preferably asurgical thread or a suture thread, absorbable or non-absorbable, of thetype used to fix or re-attach organs. For example, it is possible to usea polyester thread such as the one marketed under the brand nameErcylene®, or a polyamide thread such as Trynil®. Thus, the threadserves both for causing deformation of the tubular sleeve and also forfixation of the organs.

The tubular envelope or sleeve capable of sliding on the thread in theloop has a total length which is less than or equal to about twice thedepth of drilling in the bone, and a diameter which is less than orequal to that of the hole bored in the bone. Thus, the loop bearing thesleeve is fully introduced into the hole bored in the bone. This sleevecan advantageously be made of any deformable material, preferably onewhich has a certain elasticity, which has the property of beingimplantable, and which is absorbable or non-absorbable (for example abraided metal or plastic wire, a tube made of polyester or polyamide, ora tube made of silicone).

Depending on the circumstances, the sleeve can be made up of a singleelement or of several elements.

At the time of positioning, after introduction of the sleeve and of thethread into the hole bored in the bone, when the loop is tightened bypulling on at least one of the two strands of the thread, the latter isapplied against the sleeve and causes its deformation, changing it froma first stretched position to a second position in which it is folded onitself and in which its cross section is increased. More precisely,having folded the sleeve at its middle in such a way that the strands ofthe thread emerge in the same direction, and having introduced it thusinto the hole bored in the bone, by exerting a traction on the strandsof the thread in diverging directions, the sleeve is folded until itpresents approximately the form of a ball which, because its diameter isgreater than that of the sleeve, is compressed against the walls of thehole into which the sleeve has been introduced. By reason of thispressure, the device is then held firmly in the hole bored in the bone.

According to a simple embodiment, the sleeve in the form of a linearcylinder is slipped onto the thread, and the loop is then formed aroundthe sleeve.

In another simple embodiment, the sleeve can be preformed in a U shapeand the thread passes into the sleeve via one of its two open ends,emerges via the second end and forms a loop before passing again intothe sleeve via the first end in order to exit via the second end. In onevariant, the sleeve can include an orifice extending through its wallnear each of the two ends, and the thread can pass into the sleeve, thenemerge therefrom via one or other of its orifices. In this latterembodiment, if the orifices are arranged asymmetrically with respect tothe center plane of the loop, the traction exerted on the strands of thethread in order to cause compression of the sleeve also results in atilting effect which adds to and reinforces the friction and blockingagainst the inner walls of the hole bored in the bone.

These orifices are arranged symmetrically with respect to the middle ofthe deformable sleeve, near to the ends, or in its central part. It ispreferable to provide two orifices arranged in the same diametricalplane of the sleeve.

According to another embodiment of the invention, the sleeve is in theform of a toric ring which has at least one orifice extending throughits wall for the passage of the two strands of the thread. In thisalternative embodiment, the thread passes into the sleeve via theorifice, forms a complete loop along the inside of the annular sleeve,and emerges via the same orifice.

The sleeve is preferably reinforced in the zone where the thread passesinto it, that is to say on the periphery of each of its ends, or aroundthe orifices made in its wall, as appropriate. This reinforcement can beobtained, for example, by providing an extra thickness of material or byadhesive bonding or welding of a strip having greater strength.

The tubular sleeve can be open at its two ends, or by contrast can beclosed. In this case, it includes at least two orifices in its wall forthe passage of the strands of the thread. The wall of the tubular sleeveis preferably traversed by at least two orifices for the passage of thestrands of the thread, these orifices being arranged in such a way thatthe traction exerted on the strands of the thread causes a tiltingmovement of the sleeve, promoting its anchoring against the walls of thehole bored in the bone.

The ancillary instrument for positioning the anchoring device accordingto the present invention essentially comprises a rod capable of carryingthe thread and its sleeve for introducing them into the hole bored inthe bone, as well as a slotted cylindrical component enclosing thethread and the sleeve and capable of sliding on the rod along a distancecorresponding to the depth of the hole.

According to a preferred embodiment, the sliding of the cylindricalcomponent is guided by a rib formed on the rod and cooperating with theslot.

According to another characteristic of the present invention, theancillary instrument comprises a handle which is integral with the rodand which has a grip part facilitating its manipulation.

The sliding cylindrical component is made of a material compatible withuse in a surgical environment.

The ancillary instrument for positioning of the anchoring device of theinvention is easily used by introducing the point of the rod of theancillary instrument, bearing the loop-shaped thread and its sleeve,into the hole bored beforehand in the bone, until the loop is fullyengaged in the hole. After withdrawing the point from the hole, whileleaving the thread and sleeve therein, it then suffices to exert atraction on one strand of the thread, while slightly holding the otherstrand still in order to cause tightening of the loop inside the hole inthe bone and deformation of the sleeve on the loop until it adopts theshape of a ball, the diameter of which is greater than that of thetubular sleeve before deformation. With the traction being continueduntil locking occurs, the deformed sleeve then finds itself compressedagainst the inner walls of the cavity.

The two strands of the thread can then be knotted, at the edge of thehole bored in the bone, in order to lock the device and prevent itsloosening, then, if necessary, attach the tendon or organ using thestrands of the thread. Moreover, when the sleeve is folded into a ballshape, as indicated above, the enlargement of its diameter compared tothe initial diameter of the sleeve, and the pleated shape of itssurface, increase the phenomenon of anchoring in the spongy substance ofthe bone, resulting in improved fastening of the device of the inventionin the bone.

As has been indicated above, the device and the ancillary positioninginstrument according to the present invention are most particularlyintended for reparative surgery of ligaments and tendons. The inventioncan also be used in gynecology, for example for fixing the uterus to thesacrum by way of a ligament.

The device of the invention is also suitable for cancer surgery, and inthis application a thread is used which can contain a radioactivesubstance such as iridium. The thread is placed in the tumor, preferablyusing a non-absorbable thread, and the latter can serve as a marker forsecondary ablation of the tumor.

Tests conducted with the anchoring device according to the presentinvention, carried out under experimental conditions, have revealedexcellent properties of fixation and resistance to traction, comparableto, or even better than, those of the best of the known devices of theprior art.

The tests were conducted on two series of devices made up of sleeves ofnon-absorbable polyester braid with heat-bonded ends, of length equal to20 mm for the 1st series, and 30 mm for the 2nd series. The sleeves havean external diameter of 1.6 mm and an internal diameter of 1.0 mm. Apolyester suture thread measuring 0.5 mm in diameter (USP 2) is slippedinside the sleeve. The ends of the thread are knotted in order to form aloop.

The sleeves bearing the thread are introduced into a series of holesmeasuring 2.3 mm in diameter and 19 mm (sleeves of 30 mm) or 11 mm(sleeves of 20 mm) in depth, bored in a fresh human humerus. The testson resistance to pulling-out in the axis of the hole are carried outusing an Adamel Lhomargy DY 34 universal traction machine equipped witha calibrated 1 kN cell. A cylindrical bar integral with the mobilecrosspiece of the machine is passed into a loop closed at the other endof the sample. The speed of displacement of the crosspiece is 5 mm/min.The tests are carried out until the device is torn from the bone supportor the thread breaks.

In all cases, the suture thread was seen to break without the sleevebeing pulled out of the hole bored in the bone. The force of resistanceto pullingout varies between 10.2 and 12 kg for the samples in the twoseries.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING

The characteristics and advantages of the present invention will becomeclearer in the following examples which relate to preferred embodiments,with reference being made to the attached drawings which depict:

FIG. 1: a diagrammatic view of a fixation thread according to thepresent invention, introduced into a U-shaped sleeve, before tighteningand deformation.

FIG. 2: a view of an alternative embodiment of the device in FIG. 1,where each strand of the thread emerges from the tubular sleeve throughan orifice near each end.

FIG. 3: a view of the device from FIG. 2 showing the shape adopted bythe tubular sleeve after a first traction on the strands of the thread.

FIG. 4: a view of another alternative embodiment of the device of theinvention.

FIG. 5: a perspective view of an ancillary instrument permittingsemi-automatic positioning of an anchoring device according to theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the anchoring device of the present invention, whichcomprises a suture thread (1) forming, in its middle part, a closed loop(2) which is capable of being tightened by simple traction on one of thetwo strands (3, 4) of the thread (1).

The thread (1) forming the loop (2) passes into the sleeve (5) via itsend (6), emerges via the other end (7), once again enters via the end(6) and emerges via the end (7) in such a way as to form a complete loopin the sleeve. The latter is made of deformable and compressiblematerial, capable of sliding on the thread. The traction on the strands(3 and 4) of the thread brings about a decrease in the length of theloop (2) until its length becomes equal to that of the sleeve (5).Continuing the traction on the strands of the thread (1), or on only oneof the strands while holding the other one still, results, on the onehand, in compression of the sleeve, whose surface forms undulationsbecause of the compressibility of the material from which it is made,and, on the other hand, in tightening of the loop (2).

The edges of the sleeve, at each of its ends (6) and (7), are reinforcedto prevent them from being notched by the thread (1) when the latter istightened. This reinforcement is obtained here simply by increasing thethickness of material.

The device is put into position using an ancillary instrument such asthe one described below. The method of positioning consists in foldingvia its center the loop (2) bearing the sleeve (5) in such a way thatthe two strands of the thread emerge in the same direction, as is shownin FIG. 1, and in introducing it via its center into the hole bored inthe bone, then in tightening it by exerting a traction on the strands (3and/or 4) of the thread (1) in divergent directions. It is preferable tointroduce the entire loop into the hole, so that no part of the sleeveprotrudes from the hole. The edges (6) and (7) of the sleeve arepreferably inserted into the hole under the surface of the corticalbone.

When the loop (2) is tightened by pulling on the strand or strands (3)and (4) of the thread, it is narrowed and the flexible sleeve (5) iscompressed inside the hole. Then, by further tightening by pulling onthe strand (3) of the thread (1), the sleeve (5) is deformed until itadopts the shape of a ball. This ball will be unable to come out of thehole through which it has been introduced into the bone because itsdiameter has become markedly larger than that of the bored hole.Moreover, this ball bears on the inner face of the cortical bone or inthe spongy bone if it is sufficiently hard.

It therefore suffices to choose a suture thread bearing a sleeve whichhas a length and a diameter permitting, by tightening of the loop (2),the formation of a ball which will bear on the hard inner face of a boneand whose diameter will be sufficiently large to withstand the stressesimposed on it.

In the alternative embodiment of the device represented in FIG. 2,instead of passing into the sleeve (5) via the ends (6) and (7), thethread (1) passes through the sleeve (6) via the orifices (8) and (9)provided near the ends of the sleeve. The two orifices (8) and (9) arepreferably situated on the same side relative to a diametrical plane ofthe sleeve.

This embodiment makes it easier to fold the sleeve on itself to form acircle, as is represented in FIG. 3. When traction continues to beexerted on the strands of the thread, this circle deforms and the sleeveforms wrinkles to adopt substantially the shape of a ball.

FIG. 4 shows another alternative embodiment of the invention where thestrands (3) and (4) pass through the wall of the sleeve (5) via theorifices (8′) and (9′) arranged like the orifices (8) and (9) of thedevice in FIG. 2, but near the central part of the sleeve. In thisalternative embodiment, the strands of the thread are preferablydirected in a direction opposite to that of the ends (6) and (7) of thesleeve, and the latter can be introduced into the hole bored in the bonevia its ends and not via its center.

The anchoring device described above is put into position effectivelyusing an ancillary instrument according to the invention, represented inFIG. 5.

This figure shows a simple ancillary instrument making it easier toplace the anchoring device in a hole which has been bored beforehand ina bone.

This ancillary instrument comprises a rod (10) intended to support theloop of the suture thread (1) in the sleeve (5), via the center of itsloop (2), to ensure its positioning in the hole bored in the bone (notshown). As FIG. 4 shows, the thread (1) and its sleeve (5) are foldedvia their center on the free end of the rod (10). This rod (10) is fixedto a handle (11) bearing a grip part (12).

The rod (10), the sleeve (5) and the thread (1) are enclosed in acylindrical component (13) which has a slot (14) along its entirelength. This cylindrical component (13) can slide on the rod (10) and itis guided by the rib (15) which cooperates with the slot (14). Thefunctioning is described below.

After the hole has been bored in the bone using a conventionalinstrument, the rod (10) bearing the loop-shaped thread (1) and thesleeve (5) is introduced into the hole in such a way that the distaledge (16) abuts against the bone, at the edge of the hole. The rod (10)is then inserted, which results in the sliding of the cylindricalelement (13) along the rib (15) until the proximal edge (17) of thecylindrical element (13) comes to bear against the shoulder (18)situated at the base of the rod (10). The sliding distance is determinedso as to correspond to the depth of the hole bored in the bone. In thisposition, the sleeve (5) is entirely inserted in the hole bored in thebone. The cylindrical element (13) may, if appropriate, be replaced by alonger or shorter element depending on the depth of boring.

The strands of the thread (1) which are fixed to thread-holder plates(not shown) integral with the handle (11) are then undone. The ancillaryinstrument is withdrawn from the hole by acting on the grip (11), thenthe strand (4) of the thread (1) is pulled in such a way as to slide thethread (1) in the sleeve (5) and to deform the latter so that it forms aball.

The positioning of the anchoring device by means of the ancillaryinstrument in FIG. 5 is done as indicated above, in a semi-automaticmanner.

What is claimed is:
 1. A surgical device for anchoring a thread or wireto a bone having a hole bored therein, comprising: a deformable tubularsleeve which is capable of deforming between a first stretched positionof low cross section and a second folded position of greater crosssection; and a thread whose middle part is in the form of a closed looppassing through the deformable tubular sleeve, and wherein thedeformable tubular sleeve is able to slide on the thread within thelimits of the closed loop.
 2. The device according to claim 1, whereinthe sleeve can be deformed into a ball by traction exerted on at leastone strand of the thread.
 3. The device according to claim 1, whereinthe length of the sleeve is less than or equal to twice the depth of thehole bored in the bone.
 4. The device according to claim 2, wherein thelength of the sleeve is less than or equal to twice the depth of thehole bored in the bone.
 5. The device according to claim 1, wherein thediameter of the sleeve is less than or equal to the diameter of thehole.
 6. The device according to claim 2, wherein the diameter of thesleeve is less than or equal to the diameter of the hole.
 7. The deviceaccording to claim 3, wherein the diameter of the sleeve is less than orequal to the diameter of the hole.
 8. The device according to claim 1,wherein the length of the sleeve is equal to at least 5 times thediameter of the sleeve.
 9. The device according to claim 5, wherein thesleeve is made up of a single linear cylindrical element that is open atboth of its ends.
 10. The device according to claim 9, wherein thesleeve includes at least one orifice extending through its walldimensioned for the passage of two strands of the thread.
 11. The deviceaccording to claim 5, wherein the sleeve is made up of a toric ring andincluding at least two orifices for the passage of the strands of thethread.
 12. The device according to claim 5, wherein the sleeve is madeup of a toric ring having at least one orifice extending through itswall dimensioned for the passage of the strands of the thread.
 13. Thedevice according to claim 10, wherein the wall of the tubular sleeve hasat least two orifices extending through it for the passage of thestrands of the thread, these orifices being arranged in such a way thatthe traction exerted on the strands of the thread causes a tiltingmovement of the sleeve.
 14. The device according to claim 11, whereinthe wall of the toric ring has at least two orifices extending throughit for the passage of the strands of the thread, these orifices beingarranged in such a way that the traction exerted on the strands of thethread causes a tilting movement of the sleeve.
 15. The device accordingto claim 12, wherein the wall of the tubular sleeve has at least twoorifices extending through it for the passage of the strands of thethread, these orifices being arranged in such a way that the tractionexerted on the strands of the thread causes a tilting movement of thesleeve.